Polyethylene glycol diacrylate

ABSTRACT

COMPOSITIONS OR AROMATIC AND ALICYCLIC POLYACRYLATE COMPOUNDS COMPRISING FROM 25% TO 90% BY WEIGHT OF A POLYACRYLATE OF THE FORMULA:   CH2=C(-R1)-COO-R-CO-C(-R1)=CH2   WHEREIN R1 IS HYDROGEN OR ALKYL OF 1 TO 4 CARBONS; AND R IS:   (CH2-CH(-R2)-O)X   WHEREIN X IS AN INTEGER OF 1 TO 5, AND R2 IS HYDROGEN OR AN ALKYL OR 1 TO 4 CARBON ATOMS; (B) CH2(CH2)YCH2O, WHEREIN Y IS AN INTEGER OF 1 OR 2;   -CH2-CH(-OH)-CH2-O-(CH2)4-O-CH2-CH(-OH)-CH2-O-, OR   -CH2-CH(-R3)-CH2-O-   WHEREIN R3 IS   -OH, OR -OOC-C(-R1)=CH2   AND R1 HAS THE SAME MEANING AS ABOVE; AND 10 TO 75% BY WEIGHT OF AN AROMATIC OR ALICYCLIC POLYACRYLATE COMPOUND ARE UTILIZED IN VARIOUS DENTAL RESTORATIVE APPLICATIONS. A PARTICULARLY SUITABLE COMPOSITION IS ONE COMPRISING BIS-GMA AND TRIETHYLENE GLYCOL DIMETHYLACRYLATE.

United States Patent 3,769,336 POLYETHYLENE GLYCOL DIACRYLATE Henry L.Lee, In, San Marino, and Donald G. Stoifey, Hacienda Heights, Calif.,assiguors to Lee Pharmaceu ticals, South El Monte, Calif.

No Drawing. Original application lVlay 24, 1971, Ser. No. 146,467, nowPatent No. 3,751,399. Divided and this application Feb. 12, 1973, Ser.No. 331,555

Int. Cl. C07c 69/54 U.S. or. 260-486 R 2 Claims ABSTRACT OF THEDISCLOSURE Compositions of aromatic and alicyclic polyacrylate compoundscomprising from 25% to 90% by weight of a polyacrylate of the formula:

wherein R is hydrogen or alkyl of l to 4 carbons; and

R is:

(CHAFHO) wherein x is an integer of 1 to 5, and R is hydrogen or analkyl of 1 to 4 carbon atoms; (b) CH2(C 2)y 2O, wherein y is an integerof 1 or 2; v

OH OH CH1( JH-CHz O CHQCHQCH] CH3 0 CH2 H-CH: 0

one comprising BIS-GMA and triethylene glycol dimethylacrylate.

This is a divisional application of Ser. No. 146,467, filed May 24,1971, now U.S. Pat. 3,751,399.

BACKGROUND OF THE HVVENTION Field of the invention This invention isrelated to aromatic and alicyclic, thermosetting acrylic resincompositions comprising mixtures" of aromatic and alicyclic polyacrylicresins with 25% to.

90% by weight of certain aliphatic and aliphatic ether diandpolyacrylates.

DESCRIPTION OF THE PRIOR ART Thermosetting acrylic esters of aromaticand alicyclic compounds have been used in the past for a variety ofpurposes including the potting of electrical coils and use in dentalrestorative compositions. Various examples of such compounds aredisclosed in U.S. 2,890,202.

The use of such acrylic resins as binders in dental restorativecompoistions is disclosed, for example, in detail in U.S. 3,066,112,U.S. 3,179,623, and U.S. 3,539,533.

3,769,336 Patented Oct 30, 1973 While such prior art acrylic resincompositions have proved quite useful, it is known that the degree ofcure and magnitude of compressive strength and other important physicalproperties that have been attained are much lower than would bepredicted theoretically.

In addition, many of such prior art aromatic and alicyclic acrylic resincompositions are extremely viscous and have gel times much longer thanis desirable for many purposes.

The viscosity of aromatic and alicyclic polyacrylate compounds has beenadjusted somewhat in the past by the addition of minor amounts ofreactive diluents such as methyl methacrylate, triethylene glycoldimethacrylate, ethylene glycol dimethacrylate, and tetraethylene glycoldimethacrylate, up to a maximum of 15% of the total amount of resinpresent. Such systems are disclosed for example in U.S. 3,066,112 andU.S. 3,539,533.

One approach disclosed in U.S. 3,539,533 for increasing the compressivestrength of such resin systems, in this case in a dental restorativecompoistion, comprises blending finely divided filler andbisphenol-A-dimethacrylate with BIS-GMA, together with a maximum amountof 15% by weight of the reactant diluent, preferably triethylene glycoldimethacrylate. The maximum compressive strength of the restorativesutilizing this approach was 35,000 p.s.i.

SUMMARY OF THE INVENTION The primary object of the present invention isto pro 0 vide improved thermosetting aromatic and alicyclic polyacrylatemolding compositions having improved handling characteristics and highercrosslink densities as well as greater compressive strength and otherphysical properties not obtained previously. It is a particular objectof this invention to provide improved dental restorative compositionsutilizing the improved resin formulations of this invention which haveimproved handling characteristics, very satisfactory gel and set times,high compressive and fiexural strengths, low degrees of shrinkage oncure, and low coeflicients of thermal expansion. In addition, they haverelatively low water absorption. Such improved resin compositions areobtained by mixing with the aromatic and alicyclic polyacrylate compoundfrom 25 to 90% by weight of a compound of the formula wherein R ishydrogen or alkyl of l to 4 carbons, hydrogen or .methyl beingpreferred, and methyl most preferred;

wherein x is an integer of 1 to 5, preferably 3, and R is hydrogen oralkyl of 1 to 4 carbon atoms, hydrogen being preferred;

(b) CH (CH CH O wherein y is an integer of 1 -oH,(JH-omocmomcmcmocmom-omo- -oH,-on-om0- 3 4 wherein R is I 1 to 4 carbonatoms, methyl being preferred, or halogen,

OH or chlorine being preferred. A preferred example of a com- 1 pound ofFormula II is:

and R has the same meaning as above. 5

CH: CH; CH; oH,=i1c-o-cHrGHoHr-0@-c--ocH=GHcm-0-G-( J=oH, ll 6 An. 6 ('5CH3=?&=O O=(IJ=CHg CH; CH: (IIa) In the above formula, the preferredmeaning of R is (a). which may be namedbisphenol-A-bis(2,3-dimethacrylatopropyl ether);

HzCHCHz-O CC=CH5 H III DESCRIPTION OF THE PREFERRED wherein X ishydrogen, lower alkyl, i.e., straight or EMBODIMENTS branched chainalkyl of 1 to 4 carbon atoms, preferably As indicated, this inventionprovides improved thermomethyl, or halogen, chlorine being preferred.The presetting acrylic resin compositions comprised of aromatic ferredmeaning of X is methyl. A preferred example of and alicyclicpolyacrylates together with from 25% to acompound of Formula III is:

H CH: (1113) 90% by weight of aliphatic and aliphatic ether polyacry-The acrylates of Formula.II may be prepared by relate compounds asdefined in Formula I above. acting BIS GMA with an excess of an acrylchloride in It is preferred that the aromatic polyacrylate contain atthe presence of a tertiary amine such as triethylamine or least 2aromatic rings in its structure and likewise that 40 pyridine.

the alicyclic polyacrylate contain at least 2 alicyclic rings Thecompounds of Formula III may be prepared by rein its structure. Amongthe preferred members of the diacting the triglycidyl ether oftrihydroxy biphenyl with aromatic polyacrylates is the BIS-GMA mentionedabove, methacrylic acid in the presence of a catalyst such as a or thedimethacrylate derived from the ethylene or protertiary amine,triphenylphosphine, or triphenylantimony. pylene oxide adduct ofbisphenol-A. Also useful are compounds of the formula:

0 X: X1 x 0 cm=c 2-ii-o-bn-om-o@-b-@-o-cn,-eH-o-ii-o=cm X3 J! is (IV) Apreferred dialicyclic is the dimethacrylate derived wherein X X and Xare either hydrogen or lower from hydrogenated bisphenol. alkyl groupspreferably comprising 4 or less carbon atoms.

Representative of aromatic and alicyclic polyacrylates Preferredcompounds of Formula IV are: bisphenol-A- bis(2-methacrylatoethyl)etherwhich is represented by the following formula:

which are utilized in the practice of this invention, besides thosementioned above, are compounds such as:

and bisphenol-F-bis(Z-methacrylatopropyl)ether which is represented bythe following formula:

(IVa) 0H, 0H. 0H, cm cm-d-o-o-bncrn-o-@-cn,-@-o-cn,bn-o-p-o=cn,

A 6 (IVs) wherein each of X and X may independently be hydro- Thediacrylates of Formula IV may be prepared by gen, lower alkyl, i.e.,straight or branched chain alkyl of either of two methods. The first ofthese is the reaction 3,769,336 6 of an acryl chloride with anappropriate bis-alcohol comwhich is1-(Z-methacrylato-l-hydroxyethyl)-3-hydroxy-4- pound in accordance withthe following reaction methacrylatocyclohexane.

Other representative compounds are of the formula: 2CH JC-Cl HO-m-OH 0 ocH,=c-g-oXo-i :-c=cn,

1 1 (VIII) CH -c-o-xl-o-o- =CHI 21101 I wherein X is selected from Inthis reaction a base may be used to remove hydrogen CH chloride as itforms. The base may be, for example, a a tertiary amine such as triethylamine or pyridine. On the PG- P,

other hand, the bis-alcohol could be pre-reacted with a base to form,for example, the disodium salt thereof 1 (a) which could in turn bereacted with the acid chloride.

A second method for forming the diacrylates of For- CH2@O@CH2,

mula IV is the transesterification of the appropriate bisalcohol withlower alkyl esters of the acrylic acids in and accordance with thefollowing reaction (m) and X is hydrogen, lower alkyl, or halogen. (5 C0 X4 0 i 2X5OH In the foregoing Formula VIII, the preferred meaning of Xis methyl. X preferably is (i); thus the compound In this method anylower alkyl ester can be used; however, in practice, X is preferably amethyl group since 0 these methyl esters are more readily available andthe CHQ C OOC -OJJC=CHQ product methyl alcohol is the most volatile.

Additional polyacrylates useful in the practice of this (Vma) inventionare compounds of the following formulae:

which is named 2,2-bis(4-methacrylatocyclohexyl)pro- CH=(|3 (|3 O 0pane, is most preferred of those of Formula VIII.

x i) H H ii x The compounds of Formula VIII may be prepared by (V) thereaction of an acryl chloride or derivatives thereof CH;=(|JCOCHzCHCHz-O0CHz-CH-CHz-OC?=CH1 X H H X (VI) and with the appropriate diol accordingto methods well H0 known to those skilled in the art. The reaction isgenerally carried out in the presence of a tertiary amine such asCH,=CCO -CHCH;OCC=CH1 triethylamine or pyridine as an acceptor for thehydrogen I chloride generated in the reaction.

H X (VII) wherein in each of the Formulae V-VII, X is hydrogen, loweralkyl, or halogen. In the foregoing Formulae V- VII, the preferredmeaning of X is methyl.

Of the compounds falling within the general Formulae V-VII above whichare useful in the practice of this invention, three compounds areparticularly preferred.

According to the present invention, from 25% to 90% of the reactivemonomers of Formula I above can be em ployed with the aromaticpolyacrylate or alicyclic polyacrylate compounds.

As the amount of polyacrylate of the above formula is reduced below 25%by weight, the compositions tend to h become unduly viscous, and adecrease in the desired (a) physical properties of the cured resin isnoted. As one exceeds the maximum of 90% by weight, objectionableCH;=CC--O 0 o-o-c=cm colors are formed as well as changes in physicalpropl A g 5 erties.

H H The preferred range of the polyacrylates of Formula I which isbis-(3-methacrylato-Z-hydroxycyclopentyl)ether; is from to y Weight ofthe Ifisin composition,

which is 1,3-bis(3-methacrylato-2-hydroxypropoxy)benwith the mostpreferred range being 40% to 60% by zene; and 70 weight of the resincomposition.

(6) Especially preferred among the polyacrylate compounds HO of FormulaI above are diethylene glycol dimethacrylate,

triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate,and the dimethacrylate formed b the re- CH, C C-OOCH CHPO C C CHI actionof methacrylic acid with the diglycidyl ether of CH3 H CH8 butane-diol.

All of the compounds defined by Formula I are available commerciallywith the exception of the dimethacrylate or diacrylate of the diglycidylether of butarie-diol, which can be prepared readily by those skilled inthe art, for example, by the reaction of an acrylic acid or methacrylicacid with the diglycidyl ether of butane-diol.

The resin compositions of this invention are usually cured by theaddition of an activator, or accelerator, and a catalyst. For mostapplications, a room temperature cure in about one-half minute to twohours is desirable.

The amount of accelerator depends upon the particular resin compositionswhich are utilized and the working time which is desired. Generallyaccelerators can be employed in amounts of 0.001 to by weight of themonomeric resins utilized. In most cases, the amount of accelerator willrange from about 0.5 to 2% by weight of the monomeric resins utilized.Usually about 0.5 to 1% by weight of the resin of an activator issufficient. Examples of accelerators which have been used aredimethyl-paratoluidine, para-toluene sulfinic acid, para-tolyldiethanolamine and other tertiary amines which are well known in theart.

Catalysts are usually employed in amounts of about 0.2% to about 5% byweight of the monomeric resins. Generally amounts of about 0.25% to 2.5%by weight of the monomeric resins are satisfactory.

Peroxide catalysts are preferably employed in amounts ranging from about1% to 2% by weight based on the weight of the resin momomers present.

While peroxide catalysts such as benzoyl peroxide are preferred, othercatalysts well known in the art may be employed.

As indicated, the polyacrylic resin compositions of this invention whenmixed with finely divided particles of an inorganic filler can beutilized as a restorative filler material, or as a dental cement, forexample, for bridges and crowns in place of commonly used silicatecements. They may be used without filler as a sealant for fissures intooth surfaces.

Where finely divided filler is employed, it is usually employed inamounts varying from about 50% to 80% or more by weight of the overallresin-filler composition.

A composition used as a filling material in lieu of amalgam commonlyused by the dentist would for example contain approximately 80% byweight of an inorganic filler and a composition used as a dentaladhesive would contain on the order of 65% by weight of inorganicfiller. Among the advantages of the resin compositions of the presentinvention is their abilit to wet and carry large amounts of fillermaterial, thus providing restoratives of extremely high tensile strengthamong other desirable properties of a dental restorative material.

Where a filler is employed, the filler may be any finely dividedinorganic solid which when dispersed through the binder system will giveimproved structural strength when the binder system is polymerized intoa cured resin. The finely divided filler may have a particle sizegenerally in the range of about 1 micron to about 150 microns. Thepreferred range is from about 1 micron to 30 microns. The best resultsare obtained where the inorganic filler is treated with a keying agentto improve the bond between the organic polymer binder and the surfacesof the finely divided filler particles. Keying agents which have beenfound highly suitable are the ethylenically unsaturated organosilanefinishing or keying agents where the filler is fused silica, glass,aluminum oxide, or crystalline quartz and the binder system is of thetype described. The finely divided filler may be treated with the keyingagent, for example, in the manner described in US. Pat. 3,066,112wherein an aqueous solution of tris(2-methoxyethoxy) vinyl silane iscatalyzed with sodium hydroxide to give a pH of 9.3 to 9.8, and thefiller treated with this solution, for example, one-half percent of thesilane by weight of fused quartz. A slurry so formed is dried at about125 C. and cooled.

Where more translucent filling materials are desired, as for the fillingof anterior teeth, glass beads, or a mixture of glass beads and quartzmay be used.

By way of illustration, when the resin compositions of this inventionare employed in a dental restorative compo sition, about 0.5 to 1% byweight based on the resin binder, or more, of an accelerator, such as,for example, N,N-di-(2-hydroxyethyl)-p-toluidine is added to the resin.A suitable catalyst, such as, for example, 1 to 2% by weight of benzoylperoxide based upon the weight of the resin binder, is mixed into thesilane treated filler material. The filler material containing thecatalyst, and the resin containing the accelerator are then thoroughlymixed together and promptly placed in a cavity to be filled. The binderwill polymerize at mouth temperature to harden the filling withinseveral minutes. Fillings formed from the restorative compositions ofthis invention have very high compressive strengths.

A useful dental fissure sealant utilizing the compositions of thisinvention comprises for example about 40% by weight of the resincomposition of BIS-GMA and about 60% by weight of triethylene glycoldimethacrylate.

Dental materials utilizing the resin compositions of this invention aremore resistant to staining and discoloration than prior materialsutilizing acrylic resins, it is believed, because they contain asignificantly lower percentage of unreacted acrylic groups.

In addition, many prior art dental restoratives utilizing acrylicresins, even in the cured state, will impart a relatively high degree ofacidity when placed in water. In contrast, water in which restorativesutilizing the resin compositions of this invention are placed remainsessentially neutral.

The resin compositions of this invention when cured also have highcompressive strengths, low shrinkage on cure, generally low coefficientsof expansion, and good color which is generally light and clear, andhave a slow response to ultraviolet light. They have a generally lowdegree of water-adsorption and fewer points of stress than the prior artresins, due to more uniform and a higher degree of cure.

The following examples describing certain representative embodiments ofthis invention will serve to further illustrate the nature of thisinvention. It is to be understood that the examples are merelyillustrative, and intended to enable those skilled in the art topractice the invention in all of the embodiments flowing therefrom anddo not in any way limit the scope of the invention defined in theclaims. Unless otherwise specified, the relationship of parts by weightto parts by volume is that of grams to cubic centimeters, andtemperatures are degrees centigrade.

EXAMPLE 1 30 parts by weight of triethylene glycol dimethacrylate, 70parts of bisphenol-A-bis(3-methacrylato-2-hydroxypropyl) ether, 2 partsbenzoyl peroxide catalyst, 1.5 parts ofN,N-di-(2-hydroxyethyl)-p-toluidine as an accelerator, and 405 parts offinely divided silica (5 ,u to 150 which has been treated with anaqueous solution of tris- (2-methoxyethoxy)vinyl silane as describedabove are mixed together. The mixture gelled in about seconds and afterone hour had a compressive strength of 47,400 p.s.i.

EXAMPLES 2-4 The procedure of Example 1 is repeated, but employingdifferent proportions of triethylene glycol dirnethacrylate andbisphenol-A-bis(3-methacrylato-2-hydroxypropyl) ether as indicated inthe following table and yielding the compressive strengths shown. Theamounts of accelerator are varied to yield gel times of approximately135 seconds.

peroxide, and 640 parts of finely divided silica (325 TEG DM/ o pr mesh)which has been silane treated as described above.

B1S-GM Al gfi The resulting mixture gels in about three minutes. The

cured composition has a Rockwell hardness of 100, a

40/60 44,200 compressive strength of 45,000 psi tensile strength of7,000 p.s.i., and flexural strength of 15,000 p.s.i. The

composition is an excellent dental restorative. 1 Parts of triethyleneglycol dimethacrylate to parts bisphenol-A-bls(3-methacrylato-2-hydroxypropy1) ether. EXAMPLE 12 EXAMPLE 5 1O Theprocedure of Example 11 is repeated, but employ- A mlxture of 50 Parts50 Parts ethylene ing 405 parts of silica instead of 640 parts. Thecured comglycol dimethacrylate, 1.5 parts N,N-di-(Z-hydroxyethyD-position has a compressive strength of 40,000 p.s.1., a 'P R f butylatedhydroxytoluene, and 0 tensile strength of 8,200 p.s.i., a flexuralstrength of Parts of finely dlvlded quartz and Parts of hydro 15,000, anadhesive strength to tooth structure (shear) of phobic colloidal silica(Aerosil R-972) are mixed in equal 15 800 psi and to gold (lap shear) of3,000 psi The amounts wlth a mlxlure of 50 parts 50 Parts position is anexcellent crown and bridge adhesive. ethylene glycol dimethacrylate, 0.1part butylated hydroxytoluene, 406 parts of finely divided quartz, 25.4EXAMPLE 13 parts of colloidal silica (Aerosil R-972), and 2.4 parts ofbenzoyl peroxide. The resulting mixture gels in about A11 effectivedental fissure sealant is P p y mixing 210 seconds and sets in 240seconds. The sample is tqgether 40 Parts 60 Parts tfiethylehe glycolplaced in water at 37 C. for 24 hours after which it has h h 'y Part5 YY YU-P a compressive strength of 41,390 p.s.i., a tensile strengthtohlldlne, and P hutylated hydroxytoluene, the

of 6,180 psi. and a modulus of elasticity (compressive sultihg mixturebeing pp to a dental Surface which mode) f 1,212,940 PM. 25 has beenbrushed with a solution of benzoyl peroxide in ethyl ether, after a oneminute etch of the dental surface EXAMPLES with a cleanser such as 50%citric acid. The cured com- The procedure of Example 5 is repeated, butemployposition has a Rockwell hardness of 90 and a compresing thevarious glycol dimethacrylates shown in the folsive strength of 18,000psi. after a 24 hour cure. lowing table with the results shown in thetable. What is claimed is:

Mechanical properties-24 hrs. 37 0., Water Reactivity Compres- Modulusof Tensile sive elasticity com- Gel time, Set time, strength, strength,presslve Ex. Monomer sec. sec. p.s.i. p.s.l. mode, p.s.i.

6 Diethylene glycol dimethacrylate.- 180 210 7, 179 37, 630 1, 145,466

7 'lriethylene glycol dimethacrylate- 135 165 6, 740 37, 422 1, 145, 500

8 Tetraethylene glycol dlmethaerylate" 135 165 6, 804 35, 200 1,008,5209 Polyethylene glycol dlmethacrylate (molecular weight of polyethyleneglycol averaged about 200) 150 210 6, 928 35, 980 1, 085, 160

EXAMPLE 10' 1. A compound of the formula:

A mixture of 101 parts of 1,4-diglycidoxybutane, 86 0 H OH 0 parts ofmethacrylic acid, 1 part of triphenylphosphine,CHFCJLOCHAHCHIOCHIOHZGHZCHOCH,(JJH CHIO (J C=CH, and 1 part oftriphenylstilbene is heated for 3 days at 40 t 0., 3 days at 65 C., and1 day at 90 C., after which time there is obtained an amber viscousliquid having a re- Wherem 1 15 hydroghh alkyl 0f 1 t0 4 Carbon fractiveindex of N 1.4768 and the weight per epoxy atomsgroup has gone up to6,250, the reaction being 97% com- A compound as claimed 111 clalm 1Whefem 1 13 plete. The dimethacrylate obtained is employed in the yresin compositions of this invention. References Cited EXAMPLE 11 UNITEDSTATES PATENTS To a mixture of 60 parts BIS-GMA, 40 parts triethylene3,539,533 11/19 Lee et a1 26047 3,629,187 12/1971 Waller 260-41 R glycoldimethacrylate, 0.1 part butylated hydroxyto-luene and 1.5 parts ofN,N-di-(Z hydroxyethyl)-p-toluidine, there is added a mixture of partsBIS-GMA, 40 parts LORRAINE WEINBERGER Pnmary Exammer triethylene glycoldimethacrylate, 2.5 parts benzoyl 60 P. J. KILLOS, Assistant ExaminerUNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO.

DATED 3, 769, 336 October 30, 1973 |NV ENTOR(S) Henry L. Lee, Jr. andDonald G. Stoffey It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 3, formula II, those portions of the formula reading m'T'CH- 0should read [SEAL] A rresr:

RUTH C. MASON Arresting Officer twen ty-third D 2) Of September I 9 75C. MARSHALL DANN (mnmissr'mu'r nflarenrs and Trademarks

